Bio-Pd(0) diverting electron from CoQ-long chain to FDH/Hase-short chain during sulfamethoxazole degradation. (November 2022)

• Record Type: Journal Article
• Authors: Wang, Jinghao; Liu, Huimin; Song, Song; Chen, Yuancai; Hu, Yongyou
• Is Part Of: Chemosphere. Volume 307:Part 1(2022)
• Publication Date: 2022-11
• Subjects: Pd(0) NPs -- Electron diversion -- Respiratory chain -- NADH/NAD+ -- Transmembrane proton gradient; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2022.135689
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Microbial electron output capacity is critical for organic contaminants biodegradation. Herein, original C. freundii JH could oxidate formate in anaerobic respiration, but lack the ability to degrade sulfamethoxazole (SMX). While the incorporation of Pd(0) could effectively improve the electron output via improving the combination between flavins and c-type cytochromes (c-Cyts), increasing the activities of key enzymes (formate dehydrogenase, hydrogenase, F0 F1 -ATPases), etc. More importantly, the presence of Pd(0) caused the NADH dehydrogenase (complex I) nearly in idle, and triggered the decrease of NADH/NAD + ratio and increase of H + -efflux transmembrane gradient, eventually resulting in the electrons diverting from CoQ-involved long respiratory chain (decreasing from 91.67% to 36.25%) to FDH/Hases-based hydrogen-producing short chain (increasing from 22.44% to 84.88%), which further intensified the electron output. Above changes effectively launched and guaranteed the high-level SMX degradation by palladized C. freundii JH, alleviating the ecotoxicity of SMX in aquatic and terrestrial environments. These conclusions provided the new view to regulate the microbial electron output behaviors. Graphical abstract: Image 1 Highlights: Pd(0) activated the sulfamethoxazole degradation capacity of Citrobacter freundii. The improved electron output was the key for sulfamethoxazole degradation. Pd(0) triggered the electron diversion to improve the electron transfer. Electron diversion depended on NADH/NAD + ratio and transmembrane proton gradient. Complex I was gradually in idle with the Pd(0) loading increased.